The present invention relates generally to methods and apparatus for discharging fluids from a body in motion, and in particular to the discharge of fluids from a vehicle.
It is known in the art to employ a drainmast to discharge unwanted or excess fluids from a moving vehicle, such as an aircraft in flight. Fluids discharged from aircraft using prior art drainmast apparatus include water-based liquids from the cabin, as well as engine-derived fluids, such as lubrication oil, hydraulic fluid and fuel. Oil droplets and air/oil mists that are expelled from the nacelle of a gas turbine engine often become attached to the outer surface of the nacelle or other portion of the aircraft skin, and may form an unsightly stain on the aircraft skin. Owners and operators of aircraft have expended substantial resources in attempting to prevent or remove such stains.
Prior art drainmasts having various configurations have been used on aircraft in an attempt to prevent discharged fluid from re-contacting the external surface (skin) of the aircraft. For example, prior art drainmasts of various designs have been employed to direct oil away from the engine nacelle, with only limited success. Such prior art apparatus and configurations include: a tubular structure aligned with the airflow and affixed to an outer portion of the mast, a drainmast having a rearward pointing fluid port, and a drainmast having a terminal cap with complex, curved geometry.
As an example, U.S. Pat. No. 6,425,554 to Moreland discloses a drainmast having a drain tube extending downwards to a curvaceous cap having both concave and convex geometry, and a recessed groove in the cap. However, the drainmast cap of the '554 patent exhibits relatively high drag, and has a complex geometry, which adds to the complexity and expense of drainmast manufacture.
As can be seen, there is a need for an improved drainmast for discharging fluid from a vehicle in motion, such as an aircraft in flight.